$16.75 off
This kit qualifies for a $25 Credit from Amazon (expires at the end of 2014 so you have plenty of time to use it). If you use Amazon a lot this is equal to around $16.75 (you can buy gift cards for 33% off as mentioned before so it isn't worth as much right now) so you price goes down to $38.25!

$10-$15 off
The kit also qualifies for a Mail in Rebate for a free exchange on your carbonater, which normally costs $15 without any coupons. Assuming you have a $5 off coupon from Bed Bath and Beyond this will save you another $10.

Your final price is now $28.25! This is an amazing price for a sodastream kit!